Self-Assembly and Chaining of Particles in Viscoelastic Liquids: Fundamentals and Applications

CBET-0828104 RangelIntellectual Merit：拟议的工作寻求我们的理解，并建立聚合物溶液（粘弹性流体）流动中小颗粒的聚集，自组装和链接特性的应用。粘弹性流体中的颗粒-颗粒相互作用与牛顿流体中的颗粒-颗粒相互作用显著不同：颗粒在牛顿流体的流动中分散，并且它们在粘弹性流体的流动中聚集。我们已经做了分析，这表明，在粘弹性液体中的颗粒链是本地和基于两个支柱;第一个是粘弹性？压力？由剪切产生的正应力产生。第二种是由于我们在二阶流体中计算的法向应力的符号的变化。不同的数值和实验将进行验证这一理论。我们将建立颗粒在粘弹性流体中聚集的颗粒尺寸、浓度、颗粒与流体的密度比、液体流变参数、流场等的极限。粒子图像测速技术（PIV）的基本假设是，粒子在流体中不会发生相互作用。这个假设对于示踪剂颗粒分散的牛顿流体是有效的，但是在颗粒聚集的情况下，它在粘弹性流体中将不起作用。这项研究将确定小颗粒跟踪流动的条件，如PIV研究中所假设的那样。了解参数的范围内发生的相互作用和链接的粒子将有利于其他几个应用在石油，复合材料，食品和制药industries.Broader影响：参与的妇女和个人的代表性不足的群体在拟议的努力将鼓励通过协调招聘新的研究生通过既定的计划在加州大学欧文分校。这些面向学生的方案旨在鼓励妇女和少数民族参与科学和工程领域，包括工程机会和多样性中心（CODE）和加州NSF路易斯斯托克斯少数民族参与联盟（CAMP）。其中一个coPI是UCI CAMP部门主任，他将在这个项目和校园里对研究感兴趣的代表性不足的STEM学生之间建立联系。该研究小组包括两名女研究生。2005年，在国际米兰大学亨利萨穆埃利工程学院注册的630名研究生中，女研究生占150名，占学生总数的24%。通过这一努力产生的研究生水平的研究机会将被用来支持这些代表性不足的研究生在工程，并提供了一个坚实的基础，为推进到博士后水平和未来的学术成就。该项目还将通过UCI的本科生研究机会计划（UROP）为本科生提供研究机会。研究人员参与该计划的历史悠久，并将确保本科生的参与，特别是在该项目的实验方面。

CBET-0828104RangelIntelectual Merit: The proposed work seeks our understanding and establishes applications of the properties of aggregation, self-assembly and chaining of small particles in flows of polymer solutions (viscoelastic fluids). Particle-particle interactions in viscoelastic fluids are dramatically different than in Newtonian fluids: particles disperse in the flow of Newtonian fluids and they aggregate in the flow of viscolastic fluids. We have done analyses which suggest that the chaining of the particles in viscoelastic liquids is local and based on two pillars; the first is a viscoelastic ?pressure? generated by normal stresses due to shear. The second is due to the change in the sign of the normal stress which we compute in the second-order order fluid. Different numerical and experimental experiments will be carried out to validate this theory. We will establish the limits of particle size, concentration, particle to fluid density ratio, liquid rheological parameters, flow field etc for which particles aggregate in viscoelastic fluids. The basic assumption of particle image velocimetry (PIV) is that small particles seeded in fluid will not interact in flow. This assumption is valid for Newtonian fluids where tracer particles disperse, but it will not work in viscoelastic fluids in situations in which particles aggregate. This study will determine the conditions under which small particles track the flow, as is assumed in studies of PIV. Understanding the rage of parameters at which interaction and chaining of particles occurs will benefit several other applications in oil, composite, food, and pharmaceutical industries.Broader Impacts: The participation of women and individuals of underrepresented groups in the proposed effort will be encouraged by coordinating recruitment of new graduate students through established programs at UC Irvine. These student oriented programs are designed to encourage the participation of women and minorities in the science and engineering fields and include the Center for Opportunities and Diversity in Engineering (CODE) and the California NSF Louis Stokes Alliance for Minority Participation (CAMP). One of the coPIs is the UCI Division Director for CAMP and he will provide a connection between this project and the underrepresented STEM students on campus interested in research. The research team includes two female graduate students. In 2005, female graduate students comprised 150 out of a total number of 630 graduate students enrolled in the Henry Samueli School of Engineering at UCI, representing 24% of the student body. The graduate level research opportunities generated by this effort will be used to support these underrepresented graduate students in engineering and provide a solid base for advancement to the postdoctoral level and future achievement in academia. The project will also provide research opportunities for undergraduate students through the Undergraduate Research Opportunities Program (UROP) at UCI. The investigators have a long history of involvement in this program and will ensure the participation of undergraduates, particularly in the experimental aspects of the project.